define(function(require,exports,module) {


            (function() {

                // Baseline setup
                // --------------

                // Establish the root object, `window` in the browser, or `global` on the server.
                var root = this;

                // Save the previous value of the `_` variable.
                var previousUnderscore = root._;

                // Establish the object that gets returned to break out of a loop iteration.
                var breaker = {};

                // Save bytes in the minified (but not gzipped) version:
                var ArrayProto = Array.prototype, ObjProto = Object.prototype, FuncProto = Function.prototype;

                // Create quick reference variables for speed access to core prototypes.
                var
                    push             = ArrayProto.push,
                    slice            = ArrayProto.slice,
                    concat           = ArrayProto.concat,
                    toString         = ObjProto.toString,
                    hasOwnProperty   = ObjProto.hasOwnProperty;

                // All **ECMAScript 5** native function implementations that we hope to use
                // are declared here.
                var
                    nativeForEach      = ArrayProto.forEach,
                    nativeMap          = ArrayProto.map,
                    nativeReduce       = ArrayProto.reduce,
                    nativeReduceRight  = ArrayProto.reduceRight,
                    nativeFilter       = ArrayProto.filter,
                    nativeEvery        = ArrayProto.every,
                    nativeSome         = ArrayProto.some,
                    nativeIndexOf      = ArrayProto.indexOf,
                    nativeLastIndexOf  = ArrayProto.lastIndexOf,
                    nativeIsArray      = Array.isArray,
                    nativeKeys         = Object.keys,
                    nativeBind         = FuncProto.bind;

                // Create a safe reference to the Underscore object for use below.
                var _ = function(obj) {
                    if (obj instanceof _) return obj;
                    if (!(this instanceof _)) return new _(obj);
                    this._wrapped = obj;
                };

                // Export the Underscore object for **Node.js**, with
                // backwards-compatibility for the old `require()` API. If we're in
                // the browser, add `_` as a global object via a string identifier,
                // for Closure Compiler "advanced" mode.
                if (typeof exports !== 'undefined') {
                    if (typeof module !== 'undefined' && module.exports) {
                        exports = module.exports = _;
                    }
                    exports._ = _;
                } else {
                    root._ = _;
                }

                // Current version.
                _.VERSION = '1.5.0';

                // Collection Functions
                // --------------------

                // The cornerstone, an `each` implementation, aka `forEach`.
                // Handles objects with the built-in `forEach`, arrays, and raw objects.
                // Delegates to **ECMAScript 5**'s native `forEach` if available.
                var each = _.each = _.forEach = function(obj, iterator, context) {
                    if (obj == null) return;
                    if (nativeForEach && obj.forEach === nativeForEach) {
                        obj.forEach(iterator, context);
                    } else if (obj.length === +obj.length) {
                        for (var i = 0, l = obj.length; i < l; i++) {
                            if (iterator.call(context, obj[i], i, obj) === breaker) return;
                        }
                    } else {
                        for (var key in obj) {
                            if (_.has(obj, key)) {
                                if (iterator.call(context, obj[key], key, obj) === breaker) return;
                            }
                        }
                    }
                };

                // Return the results of applying the iterator to each element.
                // Delegates to **ECMAScript 5**'s native `map` if available.
                _.map = _.collect = function(obj, iterator, context) {
                    var results = [];
                    if (obj == null) return results;
                    if (nativeMap && obj.map === nativeMap) return obj.map(iterator, context);
                    each(obj, function(value, index, list) {
                        results.push(iterator.call(context, value, index, list));
                    });
                    return results;
                };

                var reduceError = 'Reduce of empty array with no initial value';

                // **Reduce** builds up a single result from a list of values, aka `inject`,
                // or `foldl`. Delegates to **ECMAScript 5**'s native `reduce` if available.
                _.reduce = _.foldl = _.inject = function(obj, iterator, memo, context) {
                    var initial = arguments.length > 2;
                    if (obj == null) obj = [];
                    if (nativeReduce && obj.reduce === nativeReduce) {
                        if (context) iterator = _.bind(iterator, context);
                        return initial ? obj.reduce(iterator, memo) : obj.reduce(iterator);
                    }
                    each(obj, function(value, index, list) {
                        if (!initial) {
                            memo = value;
                            initial = true;
                        } else {
                            memo = iterator.call(context, memo, value, index, list);
                        }
                    });
                    if (!initial) throw new TypeError(reduceError);
                    return memo;
                };

                // The right-associative version of reduce, also known as `foldr`.
                // Delegates to **ECMAScript 5**'s native `reduceRight` if available.
                _.reduceRight = _.foldr = function(obj, iterator, memo, context) {
                    var initial = arguments.length > 2;
                    if (obj == null) obj = [];
                    if (nativeReduceRight && obj.reduceRight === nativeReduceRight) {
                        if (context) iterator = _.bind(iterator, context);
                        return initial ? obj.reduceRight(iterator, memo) : obj.reduceRight(iterator);
                    }
                    var length = obj.length;
                    if (length !== +length) {
                        var keys = _.keys(obj);
                        length = keys.length;
                    }
                    each(obj, function(value, index, list) {
                        index = keys ? keys[--length] : --length;
                        if (!initial) {
                            memo = obj[index];
                            initial = true;
                        } else {
                            memo = iterator.call(context, memo, obj[index], index, list);
                        }
                    });
                    if (!initial) throw new TypeError(reduceError);
                    return memo;
                };

                // Return the first value which passes a truth test. Aliased as `detect`.
                _.find = _.detect = function(obj, iterator, context) {
                    var result;
                    any(obj, function(value, index, list) {
                        if (iterator.call(context, value, index, list)) {
                            result = value;
                            return true;
                        }
                    });
                    return result;
                };

                // Return all the elements that pass a truth test.
                // Delegates to **ECMAScript 5**'s native `filter` if available.
                // Aliased as `select`.
                _.filter = _.select = function(obj, iterator, context) {
                    var results = [];
                    if (obj == null) return results;
                    if (nativeFilter && obj.filter === nativeFilter) return obj.filter(iterator, context);
                    each(obj, function(value, index, list) {
                        if (iterator.call(context, value, index, list)) results.push(value);
                    });
                    return results;
                };

                // Return all the elements for which a truth test fails.
                _.reject = function(obj, iterator, context) {
                    return _.filter(obj, function(value, index, list) {
                        return !iterator.call(context, value, index, list);
                    }, context);
                };

                // Determine whether all of the elements match a truth test.
                // Delegates to **ECMAScript 5**'s native `every` if available.
                // Aliased as `all`.
                _.every = _.all = function(obj, iterator, context) {
                    iterator || (iterator = _.identity);
                    var result = true;
                    if (obj == null) return result;
                    if (nativeEvery && obj.every === nativeEvery) return obj.every(iterator, context);
                    each(obj, function(value, index, list) {
                        if (!(result = result && iterator.call(context, value, index, list))) return breaker;
                    });
                    return !!result;
                };

                // Determine if at least one element in the object matches a truth test.
                // Delegates to **ECMAScript 5**'s native `some` if available.
                // Aliased as `any`.
                var any = _.some = _.any = function(obj, iterator, context) {
                    iterator || (iterator = _.identity);
                    var result = false;
                    if (obj == null) return result;
                    if (nativeSome && obj.some === nativeSome) return obj.some(iterator, context);
                    each(obj, function(value, index, list) {
                        if (result || (result = iterator.call(context, value, index, list))) return breaker;
                    });
                    return !!result;
                };

                // Determine if the array or object contains a given value (using `===`).
                // Aliased as `include`.
                _.contains = _.include = function(obj, target) {
                    if (obj == null) return false;
                    if (nativeIndexOf && obj.indexOf === nativeIndexOf) return obj.indexOf(target) != -1;
                    return any(obj, function(value) {
                        return value === target;
                    });
                };

                // Invoke a method (with arguments) on every item in a collection.
                _.invoke = function(obj, method) {
                    var args = slice.call(arguments, 2);
                    var isFunc = _.isFunction(method);
                    return _.map(obj, function(value) {
                        return (isFunc ? method : value[method]).apply(value, args);
                    });
                };

                // Convenience version of a common use case of `map`: fetching a property.
                _.pluck = function(obj, key) {
                    return _.map(obj, function(value){ return value[key]; });
                };

                // Convenience version of a common use case of `filter`: selecting only objects
                // containing specific `key:value` pairs.
                _.where = function(obj, attrs, first) {
                    if (_.isEmpty(attrs)) return first ? void 0 : [];
                    return _[first ? 'find' : 'filter'](obj, function(value) {
                        for (var key in attrs) {
                            if (attrs[key] !== value[key]) return false;
                        }
                        return true;
                    });
                };

                // Convenience version of a common use case of `find`: getting the first object
                // containing specific `key:value` pairs.
                _.findWhere = function(obj, attrs) {
                    return _.where(obj, attrs, true);
                };

                // Return the maximum element or (element-based computation).
                // Can't optimize arrays of integers longer than 65,535 elements.
                // See [WebKit Bug 80797](https://bugs.webkit.org/show_bug.cgi?id=80797)
                _.max = function(obj, iterator, context) {
                    if (!iterator && _.isArray(obj) && obj[0] === +obj[0] && obj.length < 65535) {
                        return Math.max.apply(Math, obj);
                    }
                    if (!iterator && _.isEmpty(obj)) return -Infinity;
                    var result = {computed : -Infinity, value: -Infinity};
                    each(obj, function(value, index, list) {
                        var computed = iterator ? iterator.call(context, value, index, list) : value;
                        computed > result.computed && (result = {value : value, computed : computed});
                    });
                    return result.value;
                };

                // Return the minimum element (or element-based computation).
                _.min = function(obj, iterator, context) {
                    if (!iterator && _.isArray(obj) && obj[0] === +obj[0] && obj.length < 65535) {
                        return Math.min.apply(Math, obj);
                    }
                    if (!iterator && _.isEmpty(obj)) return Infinity;
                    var result = {computed : Infinity, value: Infinity};
                    each(obj, function(value, index, list) {
                        var computed = iterator ? iterator.call(context, value, index, list) : value;
                        computed < result.computed && (result = {value : value, computed : computed});
                    });
                    return result.value;
                };

                // Shuffle an array.
                _.shuffle = function(obj) {
                    var rand;
                    var index = 0;
                    var shuffled = [];
                    each(obj, function(value) {
                        rand = _.random(index++);
                        shuffled[index - 1] = shuffled[rand];
                        shuffled[rand] = value;
                    });
                    return shuffled;
                };

                // An internal function to generate lookup iterators.
                var lookupIterator = function(value) {
                    return _.isFunction(value) ? value : function(obj){ return obj[value]; };
                };

                // Sort the object's values by a criterion produced by an iterator.
                _.sortBy = function(obj, value, context) {
                    var iterator = lookupIterator(value);
                    return _.pluck(_.map(obj, function(value, index, list) {
                        return {
                            value : value,
                            index : index,
                            criteria : iterator.call(context, value, index, list)
                        };
                    }).sort(function(left, right) {
                            var a = left.criteria;
                            var b = right.criteria;
                            if (a !== b) {
                                if (a > b || a === void 0) return 1;
                                if (a < b || b === void 0) return -1;
                            }
                            return left.index < right.index ? -1 : 1;
                        }), 'value');
                };

                // An internal function used for aggregate "group by" operations.
                var group = function(obj, value, context, behavior) {
                    var result = {};
                    var iterator = lookupIterator(value == null ? _.identity : value);
                    each(obj, function(value, index) {
                        var key = iterator.call(context, value, index, obj);
                        behavior(result, key, value);
                    });
                    return result;
                };

                // Groups the object's values by a criterion. Pass either a string attribute
                // to group by, or a function that returns the criterion.
                _.groupBy = function(obj, value, context) {
                    return group(obj, value, context, function(result, key, value) {
                        (_.has(result, key) ? result[key] : (result[key] = [])).push(value);
                    });
                };

                // Counts instances of an object that group by a certain criterion. Pass
                // either a string attribute to count by, or a function that returns the
                // criterion.
                _.countBy = function(obj, value, context) {
                    return group(obj, value, context, function(result, key) {
                        if (!_.has(result, key)) result[key] = 0;
                        result[key]++;
                    });
                };

                // Use a comparator function to figure out the smallest index at which
                // an object should be inserted so as to maintain order. Uses binary search.
                _.sortedIndex = function(array, obj, iterator, context) {
                    iterator = iterator == null ? _.identity : lookupIterator(iterator);
                    var value = iterator.call(context, obj);
                    var low = 0, high = array.length;
                    while (low < high) {
                        var mid = (low + high) >>> 1;
                        iterator.call(context, array[mid]) < value ? low = mid + 1 : high = mid;
                    }
                    return low;
                };

                // Safely create a real, live array from anything iterable.
                _.toArray = function(obj) {
                    if (!obj) return [];
                    if (_.isArray(obj)) return slice.call(obj);
                    if (obj.length === +obj.length) return _.map(obj, _.identity);
                    return _.values(obj);
                };

                // Return the number of elements in an object.
                _.size = function(obj) {
                    if (obj == null) return 0;
                    return (obj.length === +obj.length) ? obj.length : _.keys(obj).length;
                };

                // Array Functions
                // ---------------

                // Get the first element of an array. Passing **n** will return the first N
                // values in the array. Aliased as `head` and `take`. The **guard** check
                // allows it to work with `_.map`.
                _.first = _.head = _.take = function(array, n, guard) {
                    if (array == null) return void 0;
                    return (n != null) && !guard ? slice.call(array, 0, n) : array[0];
                };

                // Returns everything but the last entry of the array. Especially useful on
                // the arguments object. Passing **n** will return all the values in
                // the array, excluding the last N. The **guard** check allows it to work with
                // `_.map`.
                _.initial = function(array, n, guard) {
                    return slice.call(array, 0, array.length - ((n == null) || guard ? 1 : n));
                };

                // Get the last element of an array. Passing **n** will return the last N
                // values in the array. The **guard** check allows it to work with `_.map`.
                _.last = function(array, n, guard) {
                    if (array == null) return void 0;
                    if ((n != null) && !guard) {
                        return slice.call(array, Math.max(array.length - n, 0));
                    } else {
                        return array[array.length - 1];
                    }
                };

                // Returns everything but the first entry of the array. Aliased as `tail` and `drop`.
                // Especially useful on the arguments object. Passing an **n** will return
                // the rest N values in the array. The **guard**
                // check allows it to work with `_.map`.
                _.rest = _.tail = _.drop = function(array, n, guard) {
                    return slice.call(array, (n == null) || guard ? 1 : n);
                };

                // Trim out all falsy values from an array.
                _.compact = function(array) {
                    return _.filter(array, _.identity);
                };

                // Internal implementation of a recursive `flatten` function.
                var flatten = function(input, shallow, output) {
                    if (shallow && _.every(input, _.isArray)) {
                        return concat.apply(output, input);
                    }
                    each(input, function(value) {
                        if (_.isArray(value) || _.isArguments(value)) {
                            shallow ? push.apply(output, value) : flatten(value, shallow, output);
                        } else {
                            output.push(value);
                        }
                    });
                    return output;
                };

                // Return a completely flattened version of an array.
                _.flatten = function(array, shallow) {
                    return flatten(array, shallow, []);
                };

                // Return a version of the array that does not contain the specified value(s).
                _.without = function(array) {
                    return _.difference(array, slice.call(arguments, 1));
                };

                // Produce a duplicate-free version of the array. If the array has already
                // been sorted, you have the option of using a faster algorithm.
                // Aliased as `unique`.
                _.uniq = _.unique = function(array, isSorted, iterator, context) {
                    if (_.isFunction(isSorted)) {
                        context = iterator;
                        iterator = isSorted;
                        isSorted = false;
                    }
                    var initial = iterator ? _.map(array, iterator, context) : array;
                    var results = [];
                    var seen = [];
                    each(initial, function(value, index) {
                        if (isSorted ? (!index || seen[seen.length - 1] !== value) : !_.contains(seen, value)) {
                            seen.push(value);
                            results.push(array[index]);
                        }
                    });
                    return results;
                };

                // Produce an array that contains the union: each distinct element from all of
                // the passed-in arrays.
                _.union = function() {
                    return _.uniq(_.flatten(arguments, true));
                };

                // Produce an array that contains every item shared between all the
                // passed-in arrays.
                _.intersection = function(array) {
                    var rest = slice.call(arguments, 1);
                    return _.filter(_.uniq(array), function(item) {
                        return _.every(rest, function(other) {
                            return _.indexOf(other, item) >= 0;
                        });
                    });
                };

                // Take the difference between one array and a number of other arrays.
                // Only the elements present in just the first array will remain.
                _.difference = function(array) {
                    var rest = concat.apply(ArrayProto, slice.call(arguments, 1));
                    return _.filter(array, function(value){ return !_.contains(rest, value); });
                };

                // Zip together multiple lists into a single array -- elements that share
                // an index go together.
                _.zip = function() {
                    return _.unzip.apply(_, slice.call(arguments));
                };

                // The inverse operation to `_.zip`. If given an array of pairs it
                // returns an array of the paired elements split into two left and
                // right element arrays, if given an array of triples it returns a
                // three element array and so on. For example, `_.unzip` given
                // `[['a',1],['b',2],['c',3]]` returns the array
                // [['a','b','c'],[1,2,3]].
                _.unzip = function() {
                    var length = _.max(_.pluck(arguments, "length").concat(0));
                    var results = new Array(length);
                    for (var i = 0; i < length; i++) {
                        results[i] = _.pluck(arguments, '' + i);
                    }
                    return results;
                };

                // Converts lists into objects. Pass either a single array of `[key, value]`
                // pairs, or two parallel arrays of the same length -- one of keys, and one of
                // the corresponding values.
                _.object = function(list, values) {
                    if (list == null) return {};
                    var result = {};
                    for (var i = 0, l = list.length; i < l; i++) {
                        if (values) {
                            result[list[i]] = values[i];
                        } else {
                            result[list[i][0]] = list[i][1];
                        }
                    }
                    return result;
                };

                // If the browser doesn't supply us with indexOf (I'm looking at you, **MSIE**),
                // we need this function. Return the position of the first occurrence of an
                // item in an array, or -1 if the item is not included in the array.
                // Delegates to **ECMAScript 5**'s native `indexOf` if available.
                // If the array is large and already in sort order, pass `true`
                // for **isSorted** to use binary search.
                _.indexOf = function(array, item, isSorted) {
                    if (array == null) return -1;
                    var i = 0, l = array.length;
                    if (isSorted) {
                        if (typeof isSorted == 'number') {
                            i = (isSorted < 0 ? Math.max(0, l + isSorted) : isSorted);
                        } else {
                            i = _.sortedIndex(array, item);
                            return array[i] === item ? i : -1;
                        }
                    }
                    if (nativeIndexOf && array.indexOf === nativeIndexOf) return array.indexOf(item, isSorted);
                    for (; i < l; i++) if (array[i] === item) return i;
                    return -1;
                };

                // Delegates to **ECMAScript 5**'s native `lastIndexOf` if available.
                _.lastIndexOf = function(array, item, from) {
                    if (array == null) return -1;
                    var hasIndex = from != null;
                    if (nativeLastIndexOf && array.lastIndexOf === nativeLastIndexOf) {
                        return hasIndex ? array.lastIndexOf(item, from) : array.lastIndexOf(item);
                    }
                    var i = (hasIndex ? from : array.length);
                    while (i--) if (array[i] === item) return i;
                    return -1;
                };

                // Generate an integer Array containing an arithmetic progression. A port of
                // the native Python `range()` function. See
                // [the Python documentation](http://docs.python.org/library/functions.html#range).
                _.range = function(start, stop, step) {
                    if (arguments.length <= 1) {
                        stop = start || 0;
                        start = 0;
                    }
                    step = arguments[2] || 1;

                    var len = Math.max(Math.ceil((stop - start) / step), 0);
                    var idx = 0;
                    var range = new Array(len);

                    while(idx < len) {
                        range[idx++] = start;
                        start += step;
                    }

                    return range;
                };

                // Function (ahem) Functions
                // ------------------

                // Reusable constructor function for prototype setting.
                var ctor = function(){};

                // Create a function bound to a given object (assigning `this`, and arguments,
                // optionally). Delegates to **ECMAScript 5**'s native `Function.bind` if
                // available.
                _.bind = function(func, context) {
                    var args, bound;
                    if (nativeBind && func.bind === nativeBind) return nativeBind.apply(func, slice.call(arguments, 1));
                    if (!_.isFunction(func)) throw new TypeError;
                    args = slice.call(arguments, 2);
                    return bound = function() {
                        if (!(this instanceof bound)) return func.apply(context, args.concat(slice.call(arguments)));
                        ctor.prototype = func.prototype;
                        var self = new ctor;
                        ctor.prototype = null;
                        var result = func.apply(self, args.concat(slice.call(arguments)));
                        if (Object(result) === result) return result;
                        return self;
                    };
                };

                // Partially apply a function by creating a version that has had some of its
                // arguments pre-filled, without changing its dynamic `this` context.
                _.partial = function(func) {
                    var args = slice.call(arguments, 1);
                    return function() {
                        return func.apply(this, args.concat(slice.call(arguments)));
                    };
                };

                // Bind all of an object's methods to that object. Useful for ensuring that
                // all callbacks defined on an object belong to it.
                _.bindAll = function(obj) {
                    var funcs = slice.call(arguments, 1);
                    if (funcs.length === 0) throw new Error("bindAll must be passed function names");
                    each(funcs, function(f) { obj[f] = _.bind(obj[f], obj); });
                    return obj;
                };

                // Memoize an expensive function by storing its results.
                _.memoize = function(func, hasher) {
                    var memo = {};
                    hasher || (hasher = _.identity);
                    return function() {
                        var key = hasher.apply(this, arguments);
                        return _.has(memo, key) ? memo[key] : (memo[key] = func.apply(this, arguments));
                    };
                };

                // Delays a function for the given number of milliseconds, and then calls
                // it with the arguments supplied.
                _.delay = function(func, wait) {
                    var args = slice.call(arguments, 2);
                    return setTimeout(function(){ return func.apply(null, args); }, wait);
                };

                // Defers a function, scheduling it to run after the current call stack has
                // cleared.
                _.defer = function(func) {
                    return _.delay.apply(_, [func, 1].concat(slice.call(arguments, 1)));
                };

                // Returns a function, that, when invoked, will only be triggered at most once
                // during a given window of time. Normally, the throttled function will run
                // as much as it can, without ever going more than once per `wait` duration;
                // but if you'd like to disable the execution on the leading edge, pass
                // `{leading: false}`. To disable execution on the trailing edge, ditto.
                _.throttle = function(func, wait, options) {
                    var context, args, result;
                    var timeout = null;
                    var previous = 0;
                    options || (options = {});
                    var later = function() {
                        previous = new Date;
                        timeout = null;
                        result = func.apply(context, args);
                    };
                    return function() {
                        var now = new Date;
                        if (!previous && options.leading === false) previous = now;
                        var remaining = wait - (now - previous);
                        context = this;
                        args = arguments;
                        if (remaining <= 0) {
                            clearTimeout(timeout);
                            timeout = null;
                            previous = now;
                            result = func.apply(context, args);
                        } else if (!timeout && options.trailing !== false) {
                            timeout = setTimeout(later, remaining);
                        }
                        return result;
                    };
                };

                // Returns a function, that, as long as it continues to be invoked, will not
                // be triggered. The function will be called after it stops being called for
                // N milliseconds. If `immediate` is passed, trigger the function on the
                // leading edge, instead of the trailing.
                _.debounce = function(func, wait, immediate) {
                    var result;
                    var timeout = null;
                    return function() {
                        var context = this, args = arguments;
                        var later = function() {
                            timeout = null;
                            if (!immediate) result = func.apply(context, args);
                        };
                        var callNow = immediate && !timeout;
                        clearTimeout(timeout);
                        timeout = setTimeout(later, wait);
                        if (callNow) result = func.apply(context, args);
                        return result;
                    };
                };

                // Returns a function that will be executed at most one time, no matter how
                // often you call it. Useful for lazy initialization.
                _.once = function(func) {
                    var ran = false, memo;
                    return function() {
                        if (ran) return memo;
                        ran = true;
                        memo = func.apply(this, arguments);
                        func = null;
                        return memo;
                    };
                };

                // Returns the first function passed as an argument to the second,
                // allowing you to adjust arguments, run code before and after, and
                // conditionally execute the original function.
                _.wrap = function(func, wrapper) {
                    return function() {
                        var args = [func];
                        push.apply(args, arguments);
                        return wrapper.apply(this, args);
                    };
                };

                // Returns a function that is the composition of a list of functions, each
                // consuming the return value of the function that follows.
                _.compose = function() {
                    var funcs = arguments;
                    return function() {
                        var args = arguments;
                        for (var i = funcs.length - 1; i >= 0; i--) {
                            args = [funcs[i].apply(this, args)];
                        }
                        return args[0];
                    };
                };

                // Returns a function that will only be executed after being called N times.
                _.after = function(times, func) {
                    return function() {
                        if (--times < 1) {
                            return func.apply(this, arguments);
                        }
                    };
                };

                // Object Functions
                // ----------------

                // Retrieve the names of an object's properties.
                // Delegates to **ECMAScript 5**'s native `Object.keys`
                _.keys = nativeKeys || function(obj) {
                    if (obj !== Object(obj)) throw new TypeError('Invalid object');
                    var keys = [];
                    for (var key in obj) if (_.has(obj, key)) keys.push(key);
                    return keys;
                };

                // Retrieve the values of an object's properties.
                _.values = function(obj) {
                    var values = [];
                    for (var key in obj) if (_.has(obj, key)) values.push(obj[key]);
                    return values;
                };

                // Convert an object into a list of `[key, value]` pairs.
                _.pairs = function(obj) {
                    var pairs = [];
                    for (var key in obj) if (_.has(obj, key)) pairs.push([key, obj[key]]);
                    return pairs;
                };

                // Invert the keys and values of an object. The values must be serializable.
                _.invert = function(obj) {
                    var result = {};
                    for (var key in obj) if (_.has(obj, key)) result[obj[key]] = key;
                    return result;
                };

                // Return a sorted list of the function names available on the object.
                // Aliased as `methods`
                _.functions = _.methods = function(obj) {
                    var names = [];
                    for (var key in obj) {
                        if (_.isFunction(obj[key])) names.push(key);
                    }
                    return names.sort();
                };

                // Extend a given object with all the properties in passed-in object(s).
                _.extend = function(obj) {
                    each(slice.call(arguments, 1), function(source) {
                        if (source) {
                            for (var prop in source) {
                                obj[prop] = source[prop];
                            }
                        }
                    });
                    return obj;
                };

                // Return a copy of the object only containing the whitelisted properties.
                _.pick = function(obj) {
                    var copy = {};
                    var keys = concat.apply(ArrayProto, slice.call(arguments, 1));
                    each(keys, function(key) {
                        if (key in obj) copy[key] = obj[key];
                    });
                    return copy;
                };

                // Return a copy of the object without the blacklisted properties.
                _.omit = function(obj) {
                    var copy = {};
                    var keys = concat.apply(ArrayProto, slice.call(arguments, 1));
                    for (var key in obj) {
                        if (!_.contains(keys, key)) copy[key] = obj[key];
                    }
                    return copy;
                };

                // Fill in a given object with default properties.
                _.defaults = function(obj) {
                    each(slice.call(arguments, 1), function(source) {
                        if (source) {
                            for (var prop in source) {
                                if (obj[prop] === void 0) obj[prop] = source[prop];
                            }
                        }
                    });
                    return obj;
                };

                // Create a (shallow-cloned) duplicate of an object.
                _.clone = function(obj) {
                    if (!_.isObject(obj)) return obj;
                    return _.isArray(obj) ? obj.slice() : _.extend({}, obj);
                };

                // Invokes interceptor with the obj, and then returns obj.
                // The primary purpose of this method is to "tap into" a method chain, in
                // order to perform operations on intermediate results within the chain.
                _.tap = function(obj, interceptor) {
                    interceptor(obj);
                    return obj;
                };

                // Internal recursive comparison function for `isEqual`.
                var eq = function(a, b, aStack, bStack) {
                    // Identical objects are equal. `0 === -0`, but they aren't identical.
                    // See the [Harmony `egal` proposal](http://wiki.ecmascript.org/doku.php?id=harmony:egal).
                    if (a === b) return a !== 0 || 1 / a == 1 / b;
                    // A strict comparison is necessary because `null == undefined`.
                    if (a == null || b == null) return a === b;
                    // Unwrap any wrapped objects.
                    if (a instanceof _) a = a._wrapped;
                    if (b instanceof _) b = b._wrapped;
                    // Compare `[[Class]]` names.
                    var className = toString.call(a);
                    if (className != toString.call(b)) return false;
                    switch (className) {
                        // Strings, numbers, dates, and booleans are compared by value.
                        case '[object String]':
                            // Primitives and their corresponding object wrappers are equivalent; thus, `"5"` is
                            // equivalent to `new String("5")`.
                            return a == String(b);
                        case '[object Number]':
                            // `NaN`s are equivalent, but non-reflexive. An `egal` comparison is performed for
                            // other numeric values.
                            return a != +a ? b != +b : (a == 0 ? 1 / a == 1 / b : a == +b);
                        case '[object Date]':
                        case '[object Boolean]':
                            // Coerce dates and booleans to numeric primitive values. Dates are compared by their
                            // millisecond representations. Note that invalid dates with millisecond representations
                            // of `NaN` are not equivalent.
                            return +a == +b;
                        // RegExps are compared by their source patterns and flags.
                        case '[object RegExp]':
                            return a.source == b.source &&
                                a.global == b.global &&
                                a.multiline == b.multiline &&
                                a.ignoreCase == b.ignoreCase;
                    }
                    if (typeof a != 'object' || typeof b != 'object') return false;
                    // Assume equality for cyclic structures. The algorithm for detecting cyclic
                    // structures is adapted from ES 5.1 section 15.12.3, abstract operation `JO`.
                    var length = aStack.length;
                    while (length--) {
                        // Linear search. Performance is inversely proportional to the number of
                        // unique nested structures.
                        if (aStack[length] == a) return bStack[length] == b;
                    }
                    // Objects with different constructors are not equivalent, but `Object`s
                    // from different frames are.
                    var aCtor = a.constructor, bCtor = b.constructor;
                    if (aCtor !== bCtor && !(_.isFunction(aCtor) && (aCtor instanceof aCtor) &&
                        _.isFunction(bCtor) && (bCtor instanceof bCtor))) {
                        return false;
                    }
                    // Add the first object to the stack of traversed objects.
                    aStack.push(a);
                    bStack.push(b);
                    var size = 0, result = true;
                    // Recursively compare objects and arrays.
                    if (className == '[object Array]') {
                        // Compare array lengths to determine if a deep comparison is necessary.
                        size = a.length;
                        result = size == b.length;
                        if (result) {
                            // Deep compare the contents, ignoring non-numeric properties.
                            while (size--) {
                                if (!(result = eq(a[size], b[size], aStack, bStack))) break;
                            }
                        }
                    } else {
                        // Deep compare objects.
                        for (var key in a) {
                            if (_.has(a, key)) {
                                // Count the expected number of properties.
                                size++;
                                // Deep compare each member.
                                if (!(result = _.has(b, key) && eq(a[key], b[key], aStack, bStack))) break;
                            }
                        }
                        // Ensure that both objects contain the same number of properties.
                        if (result) {
                            for (key in b) {
                                if (_.has(b, key) && !(size--)) break;
                            }
                            result = !size;
                        }
                    }
                    // Remove the first object from the stack of traversed objects.
                    aStack.pop();
                    bStack.pop();
                    return result;
                };

                // Perform a deep comparison to check if two objects are equal.
                _.isEqual = function(a, b) {
                    return eq(a, b, [], []);
                };

                // Is a given array, string, or object empty?
                // An "empty" object has no enumerable own-properties.
                _.isEmpty = function(obj) {
                    if (obj == null) return true;
                    if (_.isArray(obj) || _.isString(obj)) return obj.length === 0;
                    for (var key in obj) if (_.has(obj, key)) return false;
                    return true;
                };

                // Is a given value a DOM element?
                _.isElement = function(obj) {
                    return !!(obj && obj.nodeType === 1);
                };

                // Is a given value an array?
                // Delegates to ECMA5's native Array.isArray
                _.isArray = nativeIsArray || function(obj) {
                    return toString.call(obj) == '[object Array]';
                };

                // Is a given variable an object?
                _.isObject = function(obj) {
                    return obj === Object(obj);
                };

                // Add some isType methods: isArguments, isFunction, isString, isNumber, isDate, isRegExp.
                each(['Arguments', 'Function', 'String', 'Number', 'Date', 'RegExp'], function(name) {
                    _['is' + name] = function(obj) {
                        return toString.call(obj) == '[object ' + name + ']';
                    };
                });

                // Define a fallback version of the method in browsers (ahem, IE), where
                // there isn't any inspectable "Arguments" type.
                if (!_.isArguments(arguments)) {
                    _.isArguments = function(obj) {
                        return !!(obj && _.has(obj, 'callee'));
                    };
                }

                // Optimize `isFunction` if appropriate.
                if (typeof (/./) !== 'function') {
                    _.isFunction = function(obj) {
                        return typeof obj === 'function';
                    };
                }

                // Is a given object a finite number?
                _.isFinite = function(obj) {
                    return isFinite(obj) && !isNaN(parseFloat(obj));
                };

                // Is the given value `NaN`? (NaN is the only number which does not equal itself).
                _.isNaN = function(obj) {
                    return _.isNumber(obj) && obj != +obj;
                };

                // Is a given value a boolean?
                _.isBoolean = function(obj) {
                    return obj === true || obj === false || toString.call(obj) == '[object Boolean]';
                };

                // Is a given value equal to null?
                _.isNull = function(obj) {
                    return obj === null;
                };

                // Is a given variable undefined?
                _.isUndefined = function(obj) {
                    return obj === void 0;
                };

                // Shortcut function for checking if an object has a given property directly
                // on itself (in other words, not on a prototype).
                _.has = function(obj, key) {
                    return hasOwnProperty.call(obj, key);
                };

                // Utility Functions
                // -----------------

                // Run Underscore.js in *noConflict* mode, returning the `_` variable to its
                // previous owner. Returns a reference to the Underscore object.
                _.noConflict = function() {
                    root._ = previousUnderscore;
                    return this;
                };

                // Keep the identity function around for default iterators.
                _.identity = function(value) {
                    return value;
                };

                // Run a function **n** times.
                _.times = function(n, iterator, context) {
                    var accum = Array(Math.max(0, n));
                    for (var i = 0; i < n; i++) accum[i] = iterator.call(context, i);
                    return accum;
                };

                // Return a random integer between min and max (inclusive).
                _.random = function(min, max) {
                    if (max == null) {
                        max = min;
                        min = 0;
                    }
                    return min + Math.floor(Math.random() * (max - min + 1));
                };

                // List of HTML entities for escaping.
                var entityMap = {
                    escape: {
                        '&': '&amp;',
                        '<': '&lt;',
                        '>': '&gt;',
                        '"': '&quot;',
                        "'": '&#x27;',
                        '/': '&#x2F;'
                    }
                };
                entityMap.unescape = _.invert(entityMap.escape);

                // Regexes containing the keys and values listed immediately above.
                var entityRegexes = {
                    escape:   new RegExp('[' + _.keys(entityMap.escape).join('') + ']', 'g'),
                    unescape: new RegExp('(' + _.keys(entityMap.unescape).join('|') + ')', 'g')
                };

                // Functions for escaping and unescaping strings to/from HTML interpolation.
                _.each(['escape', 'unescape'], function(method) {
                    _[method] = function(string) {
                        if (string == null) return '';
                        return ('' + string).replace(entityRegexes[method], function(match) {
                            return entityMap[method][match];
                        });
                    };
                });

                // If the value of the named `property` is a function then invoke it with the
                // `object` as context; otherwise, return it.
                _.result = function(object, property) {
                    if (object == null) return void 0;
                    var value = object[property];
                    return _.isFunction(value) ? value.call(object) : value;
                };

                // Add your own custom functions to the Underscore object.
                _.mixin = function(obj) {
                    each(_.functions(obj), function(name){
                        var func = _[name] = obj[name];
                        _.prototype[name] = function() {
                            var args = [this._wrapped];
                            push.apply(args, arguments);
                            return result.call(this, func.apply(_, args));
                        };
                    });
                };

                // Generate a unique integer id (unique within the entire client session).
                // Useful for temporary DOM ids.
                var idCounter = 0;
                _.uniqueId = function(prefix) {
                    var id = ++idCounter + '';
                    return prefix ? prefix + id : id;
                };

                // By default, Underscore uses ERB-style template delimiters, change the
                // following template settings to use alternative delimiters.
                _.templateSettings = {
                    evaluate    : /<%([\s\S]+?)%>/g,
                    interpolate : /<%=([\s\S]+?)%>/g,
                    escape      : /<%-([\s\S]+?)%>/g
                };

                // When customizing `templateSettings`, if you don't want to define an
                // interpolation, evaluation or escaping regex, we need one that is
                // guaranteed not to match.
                var noMatch = /(.)^/;

                // Certain characters need to be escaped so that they can be put into a
                // string literal.
                var escapes = {
                    "'":      "'",
                    '\\':     '\\',
                    '\r':     'r',
                    '\n':     'n',
                    '\t':     't',
                    '\u2028': 'u2028',
                    '\u2029': 'u2029'
                };

                var escaper = /\\|'|\r|\n|\t|\u2028|\u2029/g;

                // JavaScript micro-templating, similar to John Resig's implementation.
                // Underscore templating handles arbitrary delimiters, preserves whitespace,
                // and correctly escapes quotes within interpolated code.
                _.template = function(text, data, settings) {
                    var render;
                    settings = _.defaults({}, settings, _.templateSettings);

                    // Combine delimiters into one regular expression via alternation.
                    var matcher = new RegExp([
                        (settings.escape || noMatch).source,
                        (settings.interpolate || noMatch).source,
                        (settings.evaluate || noMatch).source
                    ].join('|') + '|$', 'g');

                    // Compile the template source, escaping string literals appropriately.
                    var index = 0;
                    var source = "__p+='";
                    text.replace(matcher, function(match, escape, interpolate, evaluate, offset) {
                        source += text.slice(index, offset)
                            .replace(escaper, function(match) { return '\\' + escapes[match]; });

                        if (escape) {
                            source += "'+\n((__t=(" + escape + "))==null?'':_.escape(__t))+\n'";
                        }
                        if (interpolate) {
                            source += "'+\n((__t=(" + interpolate + "))==null?'':__t)+\n'";
                        }
                        if (evaluate) {
                            source += "';\n" + evaluate + "\n__p+='";
                        }
                        index = offset + match.length;
                        return match;
                    });
                    source += "';\n";

                    // If a variable is not specified, place data values in local scope.
                    if (!settings.variable) source = 'with(obj||{}){\n' + source + '}\n';

                    source = "var __t,__p='',__j=Array.prototype.join," +
                        "print=function(){__p+=__j.call(arguments,'');};\n" +
                        source + "return __p;\n";

                    try {
                        render = new Function(settings.variable || 'obj', '_', source);
                    } catch (e) {
                        e.source = source;
                        throw e;
                    }

                    if (data) return render(data, _);
                    var template = function(data) {
                        return render.call(this, data, _);
                    };

                    // Provide the compiled function source as a convenience for precompilation.
                    template.source = 'function(' + (settings.variable || 'obj') + '){\n' + source + '}';

                    return template;
                };

                // Add a "chain" function, which will delegate to the wrapper.
                _.chain = function(obj) {
                    return _(obj).chain();
                };

                // OOP
                // ---------------
                // If Underscore is called as a function, it returns a wrapped object that
                // can be used OO-style. This wrapper holds altered versions of all the
                // underscore functions. Wrapped objects may be chained.

                // Helper function to continue chaining intermediate results.
                var result = function(obj) {
                    return this._chain ? _(obj).chain() : obj;
                };

                // Add all of the Underscore functions to the wrapper object.
                _.mixin(_);

                // Add all mutator Array functions to the wrapper.
                each(['pop', 'push', 'reverse', 'shift', 'sort', 'splice', 'unshift'], function(name) {
                    var method = ArrayProto[name];
                    _.prototype[name] = function() {
                        var obj = this._wrapped;
                        method.apply(obj, arguments);
                        if ((name == 'shift' || name == 'splice') && obj.length === 0) delete obj[0];
                        return result.call(this, obj);
                    };
                });

                // Add all accessor Array functions to the wrapper.
                each(['concat', 'join', 'slice'], function(name) {
                    var method = ArrayProto[name];
                    _.prototype[name] = function() {
                        return result.call(this, method.apply(this._wrapped, arguments));
                    };
                });

                _.extend(_.prototype, {

                    // Start chaining a wrapped Underscore object.
                    chain: function() {
                        this._chain = true;
                        return this;
                    },

                    // Extracts the result from a wrapped and chained object.
                    value: function() {
                        return this._wrapped;
                    }

                });

            }).call(this);


});